TALLAHASSEE — Senate President Ken Pruitt and House Speaker Marco Rubio stood united on the first day of the 2007 legislative session, pledging a new era of cooperation, a willingness to confront the difficult.

Reaching under the mahogany dais, Pruitt pulled out a sign: Rubio for President '08 — a friendly dig from the older politician at the35-year-old's no-limits political ambition.

One year later, the Republicans will open another session on Tuesday. But this time, the story line is not as neat or naive.

Rubio continues to eye his role as an eventual springboard to future office and Pruitt remains his willing straight man. But different philosophies and a series of battles between the House and Senate have damaged the Pruitt-Rubio collaboration. And now the pair face their toughest challenge yet: cutting the state budget by $2-billion.

Adding to the stress, they must govern as their own power threatens to wane amid preparations for fall elections. All 120 House seats and half of the 40 Senate seats are on the ballot.

Both leaders say the tensions are not personal and they stress mutual respect. But no one is expecting the 2008 session to be easy, or nearly so cordial as was promised a year ago.

"Any election year is more contentious than a nonelection year, and this one might be exacerbated by the fact that we don't have the money to spend," said Sen. Jim King, a former Senate president andveteran Republican from Jacksonville.

"This won't be an easy session," agreed the House Democratic leader, Rep. Dan Gelber of Miami Beach. "All the shortcomings are coming home to roost and you have less money to address them."

In hindsight, the two leaders, and their chambers, were never destined to dovetail.

Rubio, charismatic, quick-witted and a polished orator, takes his philosophical cues from former Gov. Jeb Bush, a fiscal and social conservative. They remain close.

Pruitt is a quieter leader with a businessman's sensibility. He's a longtime legislator with a similar history, who has seen his own conservatism ebb as he has risen in the more-moderate Senate, making him a natural partner for moderate Republican Gov. Charlie Crist.

And it was that partnership, Pruitt and Crist, that ended up mattering more in 2007 than did Pruitt and Rubio's:

• The Senate pushed the governor's planto make it easier for all homeowners to buy insurance from the state-run company. House leadership fought the change but eventually gave in.

• After months of debate on property taxes, the Senate forced the House to accept Amendment 1, a last-minute ballot measure that Rubio decried as flaccid. House Republicans wanted deeper cuts and accused the Senate of bending to concerns from local governments and schools. Approved by voters Jan. 29, the measure cuts more than $9-billion from local budgets over the next five years.

This year is lining up to offer similar disagreements.

Rubio, undaunted by last year's loss, promises another run at property tax cuts. But Pruitt says the Senate is finished with the issue.

"There will be no concerted effort from the Florida Senate to do anything other than implement Amendment 1," Pruitt recently said.

"I understand if they don't want to hear it, it won't happen," Rubio said. "But I can't allow those pronouncements to be what sets our agenda."

Similarly, Rubio wants to shrink government. The $2-billion deficit is an opportunity, he says, to cut government to a more manageable size. He wants to eliminate some state agencies and has named his top priority as a cap on government spending and revenue.

"Even as fiscally responsible as we thought we were being, we allowed state government to grow faster than the ability of our economy to sustain it," Rubio said.

But Pruitt is decidedly less vocal about the need to cut government and names top goals such asbuilding infrastructure, economic development and delivering the governor's alternative energy proposals. He also wants to pass a ballot measure asking voters to elect an education commissioner and designate the Legislature, not the Board of Governors, as the body that sets university tuition.

Rubio's other goals include scaling back the state's investment in the hurricane catastrophe fund by $3-billion, making private insurers take on more of the risk and expanding health care with fewer regulations.

This session will also feature a debate over another of Rubio's pet peeves:expanding gambling.Crist wants to expand the state's gambling offerings to help offset the deficit.

Meanwhile both Pruitt and Rubio are expected to face management challenges within their chambers, for different reasons.

Pruitt's presumed successor, Republican Sen. Jeff Atwater, faces a competitive re-election this fall against a Democratic challenger, former Sen. Skip Campbell. Campbell's candidacy breaks an unspoken rule that opponent parties don't challenge the next Senate president — and is expected to create tensions between Senate Democrats and Republicans. And Pruitt's own Republican caucus is divided over the race to eventuallysucceed Atwater.

In the House, Democrats are feeling bolder these days after picking up a net eight seats since 2006. Republicans still hold a substantial majority, but the minority party now has enough votes tothwart procedural moves and block constitutional amendment proposals from making the ballot.

Veteran legislative watchers said that despite past policy disagreements, the House and Senate are getting along far better than they have in the past, especially as compared to the years under House Speaker Johnnie Byrd.

"There are clear signs that there is some commonality on issues in the agenda," said lobbyist Ron Book of Miami, pointing out quick agreements on the first round of budget cuts.

Rubio contends his personal relationship with Pruitt is stronger than any of the presiding officers in the past decade. "There are issues that divide us, but that's just how it is," he said.

Also unclear, however, is how Rubio's future political ambitions, including a possible bid for governor, will shape the session's final debates. Term limits are forcing him out of Tallahassee at an awkward time because there is no open, higher office for him to seek until perhaps 2010.

By contrast, Pruitt, 51, will return to the Senate for two more years after he surrenders the title of president. He has said he has no further political ambitions and wants to spend more time with his family. Legislative leaders say Pruitt would be happy to leavea legacy of helping Florida's economy transition from tourism to technological industries, such as the Torrey Pines Institute for Molecular Studies, SRI International and Scripps Research Institute.

Rubio plans to practice law and return to his growing family in Miami. To keep a public profile, he already is working with a foundation modeled after his 100 Ideas for Florida's Future, an idea-gathering exercise he launched when he became speaker. He is also helping gather support for a citizens' petition tocap property taxes at 1.35 percent of taxable value.

Don't write his political history yet, he says. "Probably the most important chapter in that story is yet to be written."